Gaming on LAN with Router (Wireless?)

Okay so at the moment i have a d-link 504g wired router with 4 ports. When 5 of my friends come over for a LAN we leave one person out since there are only 4 ports. We really wanted to have all 5 people playing but all our routers only had 4 ports.

Now im moving to a new house, and i was thinking of switching to a wireless router so that my dad in the other room dosnt have to pull a cable very long into the other room so that he can use the internet.Im not too sure on this because im not sure if wireless routers make u lag since they are...erm wireless.

But anyway my question is is there any way for 5 of us to play on a wired 4 port router. I heard about this thing called a switch or something does it make extra ports or something?. Enlighten me please...or is there any other way?...is it usisng that thing called a hub?..actually what is a hub? -.-?

And regarding the wireless option it would be better for me and my dad since we wont have to drag cables but does that mean that we all have to buy the hardware to support the wireless router?.
And if i get wireless is there any way to also connect 5 people?. Using the normal network cables because i dont think my friends would want to buy wireless router gear just for a lan 4 times a year.

You would have to have a wireless card for each computer, and yes, wireless can sometimes be prone to lag and dropouts. A switch is basically just like the output of your router. If you use a four port switch plugged into a 4 port router, you can connect 7 computers.

Depending on your hardware, the other alternative might be to use XP's internet connection sharing on one of the computers.